I knew that different wavelengths refract at different rates, but I just got a really good understanding of just how much today. I unfocused my blu-ray until the beam was about as big as my palm and shined (shone? I can never remember which is correct) it at my hand, which was also illuminated by an incandescent bulb. If I look at my hand illuminated by the regular yellow-white light and focus, and then shine my unfocused laser at my hand, my hand is suddenly out of focus. Then, when I focus on my hand while shining the laser on it and then turn the laser off, my hand is once again out of focus!